The present invention relates to an in vitro culture method for culturing a fertilized ovum of a hen.
There is known a culture method where an ovum of a hen which has just been fertilized is submerged in albumen at a temperature of 41.degree. C. for the culture thereof. The ovum can be developed up to an early stage of cell division, but not up to the blastoderm stage (stage X).
In order to culture an undivided fertilized ovum of a hen, the ovum is placed in a glass container filled with a culture medium which is a mixture of thin albumen and salt solution mixed in the ratio of 3:2. The glass container is sealed with a sheet of transparent plastic film. The ovum is thereafter cultured at a temperature between 41.degree. C. and 42.degree. C.
The undivided ovum can thus be developed up to the end of the blastoderm stage (stage X). However, in this case it is necessary to take out the fertilized ovum with sufficiently formed thick albumen from a lower portion of the magnum of oviduct, 165 minutes after the oviposition, or 135 minutes after the ovulation.
The ovum which has just been fertilized is positioned in an upper portion of the magnum of oviduct. At that stage, only mucin albumen and a partical thick albumen are formed around the yolk, so that the fertilized ovum cannot be successfully developed up to the blastoderm stage (stage X) by the culture method mentioned above.